Chapter 2 Quiz

The 18 faculty members in a college math department range in age from 32 to 68. A stemplot follows: 3 2 4 8 9 9 4 0 3 5 6 9 5 3 4 7 8 9 9 6 3 8 The 1.5 × IQR rule would identify an age as a low outlier if it was less than:

10.5 years.

The percent of observations above the third quartile in a distribution is:

25%

A sample was taken of the salaries of 20 employees of a large company. The following is a boxplot of the salaries (in thousands of dollars) for this year. Based on this boxplot, the five-number summary (in thousands of dollars) is:

28, 39, 48, 60.5, 77.

A violin student records the number of hours she spends practicing during each of nine consecutive weeks: 6.2 5.0 4.3 7.4 5.8 7.2 8.4 1.2 6.3 What is the first quartile for these data?

4.65 hours

A survey of 10 students was conducted to investigate the amount of time they spend on social media each day. Students were given a timer and asked to record the number of minutes spent every time they accessed social media. The students' total times for one day are given below (in minutes). 45 57 63 79 84 92 99 105 117 145 The five-number summary for these data is:

45, 63, 88, 105, 145

Student ages (to the nearest year) in a school are as follows: Age 18 19 20 21 22 23 24 25 32 Number of students 14 120 200 200 90 30 10 2 1 What is true about the median age?

All of the answer options are correct (It is 20. It would remain unchanged if the 32-year-old was replaced with an 80-year-old. It is between the first and third quartiles.)

A teacher returns an exam with possible scores ranging from 0 to 100. The students suspect that the majority of them performed poorly on the exam and request summary statistics. The teacher provides the mean, which was 72, as a summary statistic. A total of 400 students took the exam. The teacher, after several requests, provides a boxplot of the exam scores. The students can get which of the following pieces of information from this plot?

All of the answer options are correct (the median the IQR the minimum and the maximum)

The exam scores (out of 100 points) for all students taking an introductory statistics course are used to construct the following boxplot: Based on this boxplot, which of the following statements is true?

All of the answer options are correct. (The distribution of scores is fairly symmetric. About half the students scored below 63. Nobody scored below 25.)

A sample was taken of the salaries of 20 employees of a large company. The following is a boxplot of the salaries (in thousands of dollars) for this year. Based on this boxplot, which of the following statements is true?

The interquartile range is about $20,000

For each of the states and Puerto Rico, the histogram below shows the average property damage (in millions of dollars) caused by tornadoes over a 50-year period. From the histogram, the first quartile must be:

in the interval 0-10.